Researchers are zeroing in on one important reason: the unique style of Asian-American parenting.

A visit to the University of California’s most selective campuses shows how very well Asian-American kids do academically: While Asian Americans constituted 14 percent of the state population in 2008, this fall they made up about 40 percent of the freshman class at UCLA and 37 percent of the entering class at University of California, Berkeley.

But it’s not just in California, and it’s not just in college. The 2000 Census found that 44 percent of Asian Americans had a bachelor’s degree, compared with 26 percent of the white population. Their outsize presence in higher education — critics charge some universities with enforcing tacit Asian-American quotas — has made their success legend.

In the latest report of scores from the National Assessment of Educational Progress, standardized tests administered to U.S. elementary and secondary students, finds Asian-American students have overtaken white students’ scores in reading at the high school senior level. Asian Americans had already topped white scores at the fourth-grade level in 2007 and the eighth-grade level in 2009.

Of course, there are many ethnic subgroups of Asian Americans. So a word of statistical caution: Research on parenting practices has mostly focused on East Asians — Chinese, Japanese and Koreans. University of California and U.S. Census statistics, on the other hand, include many other smaller subgroups, such as Filipinos, South and Southeast Asians, Indonesians and Pacific Islanders.

It’s also important to note that some Asian-American academic success is a product of U.S. immigration policy. Many high-performing Asian-American students have well-educated and relatively wealthy parents, admitted to the U.S. “because of the assets they were able to bring to this country,” says Robert Teranishi, associate professor of higher education at NYU.

In that vein, many students whose Vietnamese, Cambodian and Laotian (including Hmong and Mien peoples) parents are less well-off don’t finish high school, adds Teranishi, author of the just-published Asians in the Ivory Tower.

But these sociological facts don’t fully explain the huge success of Asian-American kids in American schools. Over the past two decades, a spate of studies has examined the cultural beliefs that shape Asian-American parenting, and their effect on kids’ learning. They describe a style of parental involvement that results in Asian-American kids spending more time studying than other kids.

One study, for example, found that Asian-American 11th-graders studied six hours more per week than their white peers. Another found that in 2007, more than two-thirds of Asian-American high school students did homework five or more days a week, while only about 40 percent of white and Hispanic kids, and less than a third of African-American students, did so. According to other research, Asian-American kids devote less time to chores, part-time jobs and dating than other kids.

In these cultures, this goal of self-improvement still holds sway: While a majority of white college students surveyed by Li defined knowledge as facts, information, skill and understanding of the world, 79 percent of the Chinese college students defined it as “a way to self-perfection” and “spiritual enrichment.”

Transmitted down through the generations, this “moral mandate” for self-improvement “has tremendous motivational impact,” the Brown psychologist says.

Such veneration of diligence helps account for the widespread Asian belief that when striving for academic success, effort counts more than innate ability.

American students of most ethnicities, other researchers have found, tend to believe the reverse, often arguing that gifted people are so smart they don’t have to work as hard as others do. Americans also often think that we’re born smart or not — with a fixed intelligence — while Asians more often believe that studying makes a person smarter. As one high-achieving Chinese-American student told Li, “Everybody in my family, all my aunts and uncles and cousins, they’re all like, ‘If you try harder, you’d be like a really smart person.’”

Li showed that even preschoolers value effort and ability differently according to their culture when she asked 95 white Americans and 93 mainland Chinese 4- to 6-year-olds to finish a story about a bird learning how to catch fish. The white children tended to mention the bird’s ability and strategies (“She needs to know how to catch fish first,” said one.)

The Chinese children, on the other hand, commented more on the bird’s diligence, persistence and concentration. “Little Bear can never catch fish if she stays with three hearts and two minds,” said one. “He fell, but he is not afraid, and starts all over again until the end,” said another.

Both the Chinese and Japanese cultures also embrace the idea that children are like seedlings, and need parental shaping and trimming as they grow. (Japanese uses the same character for “cultivating” a plant and a person.)

Parents shouldn’t start training children too young — the seedling has to sprout — but early habits will dominate, goes the common conviction. That’s why 60 percent of Asian-American parents in one study by Michigan State University education professor Barbara Schneider taught their preschoolers basic reading, writing and math, hoping also to imbue them with perseverance, concentration and focus.

In contrast, 16 percent of whites surveyed taught their preschoolers those basic skills. Many explained that they didn’t want to push academics on their preschoolers because they worried about “baby burnout” — squelching their toddlers’ motivation with too-early teaching.

Confucius also valued harmonious relations, achieved when people fulfill the responsibilities of their hierarchical roles. That means children owe respect and obedience — “filial piety” — to their parents, who in turn must “govern, teach and discipline” them responsibly and justly, explains Chao, author of a seminal 1994 article published by the journal Child Development. That translates, she says, into children honoring their family by succeeding in school. Parents in turn deem their top parental responsibility is educating their children well.

Chinese parents carry out this responsibility by relying on the notion of guan — which literally means “to govern” or “control” — but also denotes “to care for” and even “to love.”

“Guan,” Chao explains, “is about guiding and managing children and their behavior and their lives.”

The chief aim of guan is to guide kids to get a good education, especially since until the early 20th century scholarship in China led to politically and economically powerful government posts. Asian-American parents still value education extremely highly, telling their children, “Education is the only means to a good life.”

“Particularly for East Asians,” Chao says, “their efficacy in parenting is judged by how well their children do in school.”

Such cultural beliefs and responsibilities lend Asian-American parents’ involvement in their children’s education a particular style, as Chao found when she compared the practices of 123 immigrant Chinese and 64 white parents of first-, second- and third-graders from four Los Angeles school districts. Did they check their children’s homework? Go to PTA meetings? Volunteer in the classroom? Watch them in sports or other extracurricular activities? Buy them extra workbooks?

While the white parents tended to emphasize “hands-on” supervision — checking up on homework, attending school meetings and watching their kids in extracurricular activities — the Chinese parents spent more time on creating an educational environment in the home. They gave their kids a place to study, as well as extra homework, books and computer programs, and took them to music lessons and Saturday language and culture school.

After the elementary years, this difference becomes even starker.

As early as fifth or sixth grade, many Asian-American parents expect that their children will know how to organize themselves and study on their own, and by high school that feeling is almost universal, Chao says.

But as Chao found when she followed 2,111 ninth-graders through their sophomore and junior years, the Asian-American parents gave their high school kids far more indirect support at home than did their white counterparts. They focus more on college planning and preparation like SAT and ACT courses, and save more money for college.

“They’re talking about possible majors, asking ‘Where are you going to apply?’ and visiting colleges,” Chao says. “They’re proactively planning for the next step.”

Even low-income Asian-American families provide a great deal of indirect, out-of-school support, Li found when she studied 32 Massachusetts ninth-graders whose Chinese immigrant parents worked as cooks, custodians, shelf stockers and nursing home aides.

While few of these parents checked their children’s homework or attended school meetings, they networked with co-workers and other parents, and relied on an older sibling or another relative for tutoring and academic advice. The parents also talked up role models, which Li found gave their kids a sense of confidence rather than creating jealousy or competitiveness. The students’ GPAs averaged 3.27.

“Then we asked, ‘Does that help you in any way to work harder?’ They said, ‘Yes it does.’ We wouldn’t expect this answer from European-American kids. This surprised us.”

Li concluded that these students understood how much their parents sacrificed for their education, and also that their parents conveyed — like sports coaches yelling “Do it!” on the sidelines — that they’re capable of achieving.

“[That] really drove home how they come to terms with this kind of bugging,” says Li, who adds that she doesn’t know if kids with higher-income parents would react the same way.

Furthermore, these low-income parents expected relatives to join in exercising guan. “Be good in school,” one high-achieving boy said his grandmother and uncles often urged him. “Don’t do anything stupid, do all your homework.”